Constant speed dynamoelectric power transmission unit



May 18, 1948. L.v A. TROFIMOV CONSTANT SPEED DYNAMCELECTRIC POWER TRANSMISSION UNIT Filed Oct. 25, 1942 3 Sheets-Sheet 1 IllllIIIllllllllll'lllllllIllllllllllllllllllllll y 8, 1948. A. TROFIMOV 2,441,605

CONSTANT SPEEP DYNAMOELECTRIC POWER TRANSMISSION UNIT Filed Oct. 23, 1942 3 Sheets-Sheet 2 Lev/7 Z a/know 5 g fly W/ Patented May 18, 1948 CONSTANT SPEED DYNAMOELECTRIC POWER TRANSMISSION UNIT Lev A. Trofimov, Willoug'hby, Ohio Application October 23, 1942, Serial No. 463,019

4 Claims. (Cl. 318-146) This invention relates to power apparatus for driving a load at constant speed by power supplied by a power source at variable speed.

In the various arts loads are driven at variable speed and a variable speed motor (electric motor, internal combustion engine, etc.) is provided as the source of power. It is desirable in some cases, however, to utilize power from this same variable speed power source to concurrently drive a load at constant speed.

An illustration of such a case would be, 'the driving of a primary load by a variable speed internal combustion engine and the driving of an auxiliary load such as an electric generator at constant speed by a power take-off from the engine.

In other cases, it is desirable to drive a primary or sole load at constant speed from a variable speed power source.

Considered apart from the power source, the invention herein described is a power transmission unit; and considered with the power source, the invention is a power supplying apparatus generally.

It is among the objects of the present invention:

To provide generally an improved. power apparatus by which a load may be driven at constant speed by a power supplying motor operating at variable speed;

To provide generally an improved power transmission for transmitting to a load to drive it at constant speed, the power of a power source supplied at variable speed;

To provide an improved power transmission or power supplying apparatus comprising an electric alternator element driven or arranged to be driven at variable speed, a power delivering electric induction motor element driven by electric power supplied thereto by the alternator, and means responsive to the speed of the motor element to control the power supplied by the alternator to maintain the speed of the motor element substantially constant;

To provide an improved power transmission mechanism comprising a variable speed directcurrent field element arranged to rotate within an alternating current type stator and to produce a rotary magnetic field therein; and an a1ternating current type rotor element arranged to rotate within the stator element and to be driven by the rotary field;

To provide an improved power transmission mechanism comprising a variable speed directcurrent-energized field element arranged to rotate within an alternating current typev stator and to produce a rotary magnetic field therein; and an alternating current type rotor element arranged to rotate within the stator element and to be driven by the rotary field; and comprising governing means by which the energization of the direct current field. element is weakened responsive to tendency of the rotor element to increase in speed, and vice versa;

To provide an improved power transmission mechanism comprising an alternating current type stator and a power delivering rotor rotat able therewithin by a magnetic field in the stator which rotates at variable rotational velocity; and comprising means to weaken the strength of the rotating field responsive to tendency of the rotor to increase in speed, and vice versa;

To provide an improved power transmission supplied with power from a variable speed source and delivering power at constant speed and in which a double transformation of power is provided whereby the torque supplied by the source may be different from the delivered torque.

Other objects will be apparent to those skilled in the art to which my invention appertains.

My invention is fully disclosed in the following description taken in connection with the accompanying drawing in which;

Fig. 1 is a diagrammatic view illustrating an embodiment of my invention and showing in some detail a governor associated therewith;

Fig. 2 is a View similar to Fig. 1 illustrating the embodiment of Fig. l in a diiferent environment of use, in which the governor, which is indicated diagrammatically only, performs functions additional to those which it performs in the showing of Fig. 1;

Fig- 3 is a diagram of speed and torque by which some of the operative functions of the embodiments of Figs. 1 and 2 may be better understood;

Fig. 4 is a diagrammatic View illustrating a more generalized embodiment of my invention than that shown in Fig. 1;

Figs. 5, 6, '7, and 8 are views illustrating governors of diiferent forms which may be substituted when desirable for the governor of Fig. 1;

Fig. 9 is a longitudinal sectional view of an actual mechanism or apparatus by which the embodiment of Fig. 1 may be practiced.

Fig. 10 is a fragmentary view with parts broken away and parts in section taken from the plane I!) of Fig. 9.

Referring to Fig. 1 of the drawing, I have shown at I a shaft the rotational velocity of source of rotational power which operates at variable speed and drives at variable speed a shaft 3 from which power to drive the shaft I is derived. The power source 2 may drive a primary load not shown. by means. of.' at. shaft- 4, in which case the shaft 3 would be an' auxiliary power take-off shaft; or the shaft 3 may be itself the primary power supplyin shaft of the source- 2 At 5 is a stator element of the alternating.

current type, that is to say it comprises a tubular body 6 of laminated steel having endplates'W-J? and bar type conductors 8-8. extending through. perforations in the laminations and connected" to the end plates 1-1.

Driven by the shaft 3? or mounted thereon is arotary field element 9. of the direct current. type. comprising pole pieces I0..in which a. magnetic field is produced by direct. current field windings. II-II which, in the present embodiment are ,4 rent field element 9, so that there is in the stator and rotor 20, a rotating magnetic field very similar to the rotating magnetic held in the stator and rotor of an ordinary commercial squirrel cage induction motor.

This rotating stator field,reacting upon the conductor bars 2323 of the rotor 20, generates current therein which reacting upon the field itself developes rotational torque'atztherotor 20 causing itto rotate, the action being similar to that of a squirrel cage induction motor. The shaft I is thus rotated.

For. reasonswhich will become apparent hereinafter, the. rotor bars 23-23 or the short circuited' electric circuits thereof including the bars and'theendplates 2222, are designed to have relatively, high resistance, so that for a given rotational'speedof the shaft 3 and direct current fieldlelement 9, the torque curve of the rotor 20 as its speedchanges starting from rest and comingup to. the speed of the rotating alternating field,.is approximately that shown by the curve 29 in Fig, ,3; wherein .assliown, when the rotor is at rest the torque, at 30, is ofasubstantial value suppliedlwith currentfrom direct currentmains and. rises-as the rotor speeds up untilthe rotor I2 and I3, .the-degreeof energization beingunder the control of a rheostat shown'generally at. I4 and comprising a resistor I5.and'an.arm Ilimovable thereover, the energizing circuitbeingfrom the main I2 by a.wire I1 to-and through the 0 windings II. in series andby av wire I8. to. the

resistor I5, through'a portion of it to the arm.

IS-and by a wire I9, to the. supply main I3.

Rotatable within the stator 5 is alsoa. rotor element 20. of the alternating current type and.

this may-have the construction of the rotor of an. ordinary commercial squirrel cage induction motor. This rotor therefore comprisesabody of laminated steel, 21, end plates 2L-22connected.

by-bars 23-23 extending through perforations 4p,

in.- the laminations and connected to=the end plates 22-42. The rotor 20 is mountedupon or drivingly connectedwith the shaft I.

It will be'observed that ee -illustrated in-Fig.

1, the shafts 3, and I- axially aligned but sepa-ratefrom each other-iandthat the stator 5 is of sufiicient axial extent. to. surround both the. direct current field 9 and'thealternating current rotor 20.

There. may be any desired or suitable number 50.-

of poles and windings for the direct current field element 9, and any suitable number of conductor bars 8 and 23 although only two of each are illustrated. The-barsli are preferably equally spaced around the-axis of the'tubular. stator, and the.bars 55.

23 equally spaced around the. axisof the rotor; the stator and the rotor thus both being of' the so-called squirrel cage construction which term it is believed will identify the type, characteristics, and construction of these elements tothose skilled in the art without further illustration ordescription.

In theoperation of the embodiment of Fig. 1 thus far described, rotation-ofthedirect'current fieldelement 9, generatesalternating current in 35 correspondence with rotation. of. the d rect; cur-- 73:.

speedis. approximately 40% of the synchronous speed. (that isto say,.the speed of the rotating alternating magnetic. field) asshownat 3|; and from thereon, as the rotor. speeds up, the torque decreases along the line 32'andbecomes zero as at 33,.when andifthe rotor rotates at synchronousspeed. The curve 29'asthus described is substantially. the same. as the torque-speed curve of a squirrel cage induction motor when the electricalpath of the short circuited bars of the rotor has suitable resistance; and the rotor 20 is preferably. so designed as to have a torque-speed curve of these characteristics by giving to it the necessary quantitative electrical values as well understood by those skilled in this art.

For purposes .of illustration and description, it will be assumedthatthe minimum speed at which the shaft 3 willrotate is that represented by the speed D-33 in Fig. 3; and it will be assumed that the maximum torque necessary to be developed at the rotor 20 to drive the load connected to the shaft I will berepresented-by the line 34 of Fig. 3. To drive this load and develop this torque, the rotor 20 will lag behind the rotating alternating field and run at a speed represented by the speed point 35, Fig. 3, just as the rotor of a squirrel cage induction. motor lags behind its rotating field,

The speed 0-45, Fig. 3 may therefore; be taken as the selected constant speed at'which the shaft I. is to rotate for different loads thereon or changes of speed of the power source shaft 3. Suppose'therefore that the power supplying shaft 3..should.increasein speed-for example to double its speed. This will cause the speed of rotation Of thealternating field tov increase to the speed 0-36-of Fig. 3; and with the same energization of the field windings I I--I I, the-torque developed at the rotor 20 would have the characteristics indicated fragmentarily at 31, and the rotor 20 would accordingly-rotate at approximately double its: desired speed; but if concurrently with the increase of, speed of the direct current field, its energization: be suitably decreased, the torque curve at the increased input speed, may be brought down. to that shown by the curve 38,

which curve crosses the torque curve 34 at 39; so that the torque necessary to drive the load will againbedeVeloped at the speed 0-35. Thus at differentispeedsgof the inputshaft 30, there are corresponding values of energization for the field windings II at which the rotor and load shaft I will rotate always at the same speed.

In the embodiment of Fig. 1 this accomplished by means of a governor shown generally at H which, upon any change or tendency to change of speed of the load shaft I, the rheostat I4 is operated to make a corresponding change in the energization of the field win-dings I I to maintain the speed of the load shaft I constant.

The governor comprises a vertical floating shaft 42 having a spline connection with a bevel gear 43 resting upon and rotatable in a bracket 44 on a main frame 45. The gear 43 supports a housing 46 in the upper portion of which is a spring 41 counterbalancing and suspending the shaft 42, and parts associated therewith, the tension of the spring being adjustable to this end by a screw 48 in the upper part of thehousing 4B.

The gear 43 is rotated by a bevel gear 49 connected to or forming part of a gear 50 rotatable on a shaft 5|, the bearings for' which have been omitted for simplicity, and the gear 56 being meshed with a gear 52 on or rotatably connected to the load shaft I.

Suitably mounted .on the main frame 45 and co-axial with the floating shaft 42 is apair of vertically spaced bevel gears 53 and 54 meshed with a bevel gear 55 mounted upon a governor shaft 56 connected to the rheostat arm I6 to rotate it over the resistor I5. Friction discs 51 and 58 connected to or mounted on the floating shaft 42 and slightly spaced respectively from the gear 53 and a flange 59 on the gear 54, are moved, one or the other, into frictional driving engagement with a corresponding bevel gear 53 or 54, upon 52, 50, 49 at a Velocity determined by that of the shaft I. The balls 6060 are subjected to the action of centrifugal force due to this rotation and have been illustrated in the positions which they occupy when the shaft I is rotating at the desired constant speed.

If the speed of the shaft I should tend to increase slightly, the balls 60-60 will be thrown outwardly away from the shaft 42, nd the fingers 6| will press downwardly upon the upper end of the shaft 42 in opposition to the spring 41, and move the shaft downwardly engaging the friction disc 51 with the gear 53, thereby driving it and through it driving the gear 55 and the governor shaft 55, to operate the rheostat I4 in the direction to weaken the field windings II--I| for the purposes described. If the speed of the shaft I should fall or tend to fall below the desiredspeed,

the balls 6li69 will be moved inwardly toward. the shaft by the spring 41, thereby causing the,

shaft 42 to rise and engage the friction disc 58 with the flange 59 on the gear 54, driving the gear 54 and thereby turning the governor shaft 56 in the other direction to strengthen the energization of the windings I I-I I.

In this manner, the weakening or the strengthening of the field winding energization goes on until the shaft I again attains or'is maintained at the desired constantspeed, at which speed, the shaft 42 is again balanced in its intermediate position at which the friction discs 51 and 58 are out of,engagement with the gear 53 and the flange 59, whereupon the rheostat arm I6 remains in the position to which it was last adjustably moved.

In the foregoing the tendency of the shaft I to change its speed upon a change of speed of the shaft 3 has been described. In a similar manner, the shaft I will tend to change its speed if the load driven thereby should change in amount, but it is believed that it will now be clear that whatever the cause of the tendency of the shaft I to change its speed, the governor will operate to accordingly change the energization of the field windings II to restore the speed of the shaft I to or maintain it at the preselected constant value.

The actual speed at which the shaft I rotates and at which it is maintained may be adjustably varied by adjusting the tension of the spring 41- by the adjusting screw 48 as will be understood, since this changes the speed at which the shaft 42 must rotate to hold the balls 6il60 in the position at which the friction discs are disengaged from their associated gears.

It will be apparent that there is in the embodiment of Fig. l a double transformation of power, namelyi mechanical power at the shaft 3 is converted into electrical power in the stator 5 and this is converted back into mechanical power in the rotor 20. Because of this double transformation, the speed and torque at the shaft 3 may be different from that at the shaft I as described above. Power put in at the shaft 3 may be power at high speed and low torque or low speed at high torque, while the output power at the shaft I may be constant speed at all times and at higher or lower torque depending upon the load driven; and the torque driving the direct current field 9 may therefore differ widely from the torque driving the rotor 20.

It will be apparent therefore that the characteristics of the thransmission of power from the shaft 3 to the shaft I is radically different from that which would be provided by merely a magnetic coupling between the two, such as has heretofore been disclosed and in which the input torque and the output torque must of necessity be at all times equal.

In the embodiment of Fig. 1, the governor M in maintaining the speed of the shaft I substantially constant, corrects for changes of speed of the input shaft or of load on the shaft I.

In some cases, there are other factors or cir-v cumstances of environment which must be corrected, to maintain the shaft I at substantially constant speed, and illustrative of these are those shown in Fig. 2. In this figure, the windings I I'-! I are energized, not from supply mains but from a direct current generator 62 driven by the shaft 3; and the generator 62 besides supplying current to the field windings may also supply current to an electrical load 63; and the load driven by'the load shaft I may be an electric generator such as an alternator 64 supplying current to a load circuit 65.

Insuch an environment, variations of speed of the input shaft 3, besides changing the speed of the direct field element 9, will change the speed of the generator 62, causing it to vary the energization of the windings I I or the electrical load 63 may be extraneously varied; or the electrical load on the generator circuit 65 may vary.

accuses Variations of any oneor: any number of. these four: factors: will: cause; the. load-i shaft I to tend to change; its speed, and the alternator 64 may be" supplying current to a. load the alternating frequency of which-must forvarious reasons he maintained substantially constant. But with the arrangement illustrated, no matter What cause or combination of causes tend to make the load shaft I- change its speed, they will be correctedby. thegovernor M to maintain the speed of the shaft I constant.

While Iv prefer to embody my invention in a unitary structurein whichthe direct current field element and the alternating current rotor revolve within a common stator as described above and to be hereinafter further described in connection with Fig. 10 this isnot in every case essential. The direct current field element may be in one unit driven by the shaft 3, and the rotor 29 may be in another unit connected to the load shaft I; thisbelng illustrated in Fig. 4 diagrammatically.

The direct current field element 9 driven by the shaft 3 and energizedby the field windings I I-I I rotates within awinding of the distributed type, shownat G8, and generatestherein three-phase alternating current which is supplied by external wires 51, 88; 89'to a separate distributed winding III within which rotates a squirrel cage type rotor II connectedtothe load shaft I.

Obviously, with this arrangement the Winding H1 will produce a rotating magnetic field, rotating'at the velocity of the direct current field element '9, and the operation will be substantially the same as that of the embodiment of Fig. l. The rest of Fig. 4 has been iventhe same referencecharacters as Fig. 1 and it is thought that it is unnecessary to further describe it.

In the foregoing embodiments of my invention a governor 4| has been illustrated and described in detail and this same governor has been indicated as associated with the various forms. It will be understood, however, that other types of governors having other modes of operation may be employed and in Figs. 5 to-8 inclusive other governors are illustrated;

These governors in each case rotate a governor shaft 56; and therefore such governors may be applied to the forms previously described instead of the governor 4|. The governors of Figs. 5, 6, and 7 have in common the feature that they are actuated by electric current or electric potential produced by a generator driven by the load shaft I. In each instance, this governor generator may be a generator of small size andoutput provided especially for actuating the governor, in which case the main load driven by the load shaft I would be another and different load; or the main load contemplated to be driven by the load shaft I may be an electric generator in which case potential of the main load generator may be used to actuate the governor. The generators driven by the load shaft I in Figs. 5, 6, and 7 may there fore be considered as governor generators or as main load generators driven by'the load shaft I.

In Fig. 5 the governor is shown somewhat diagrammatically. The governor shaft 56 referred to is driven in one direction or the other by a bevel gear I8 constantly meshed with axially aligned'bevel gears (Sand 80. A vertically floating shaft 8I passes through the bevelgears 'I-9 and 88 and is driven by a gear 82 splined thereon, the gear 82 being driven through gears 84, and 85 by the load shaft I.

The floating shaft 81 has thereon and between the bevel gears I9 and 80, friction discs 86 and 81 slightly spaced respectively from the bevel gears 19 and and the shaft 8I is normally suspended to dispose the discs in this relationship by a magnetic plunger 88 in a winding 89.

The plunger 8| has a stem '90 abutting upon a block 9| which is engaged by one end of a compression spring '92 the other end of which spring engages an adjusting screw 93 by which'the compression tension of the spring may be adjusted. The winding 89 is energized across the terminals of anelectric generator 94 driven by the load shaft I.

By this arrangement the desired constant normal speed of the shaft I will, by driving the generator 94, cause it to generate a normal potential which, energizing the winding 92, will cause it to counter-balance or support the floating shaft 81 with the friction discs 86 and 8"! normally disengaged from both of the bevel gears I9 and 80; and this may be adjustably determined for the shaft 8! by adjusting the spring 82 which opposes the pull of the winding 89 on the plunger 88.

If the load shaft I should tend to increase in speed, it will tend to increase the voltage on the winding 89 and cause it to raise the floating shaft SI from its normal position; or if the load shaft speed should tend to decrease it will allow the floating shaft to be moved downwardly. In one case or the other the friction discs 858'I will engage the gear I9 or the gear 89, and as will be understood, this will rotate the governor shaft 56 in one direction or the other, moving the rheostat arm I6 over its associated resistor I5. This has the effect, as described above, of neutralizing the tendency of the shaft I to change its speed, bringing it back to or holding it at its preselected constant speed.

The governor shown in Fig. 6 drives the governor shaft 56 and rheostat arm I6 for the purposes described by means of a double differential gearing mechanism shown generally at 95. This mechanism comprises two spider elements 96 and 9'! rotatably supporting, respectively, pairs of pinions 9893 and 99-99. Meshed with the pinions 98 are differential gears I80 and IOI; and meshed with the pinions '99 are differential gears I02 and I83. The differential gears I09 I02 are connected respectively to pinions I84 and I05 both of which are meshed with a gear I88 on the governor shaft 56. A pair of metallic discs I0? and I08 are connected to the differential gears IOI and I03 respectively.

Electro-magnets I09 and III], having energiz ing windings I I I and I I2, are provided with poles pieces adjacent to opposite sides of the discs as illustrated, whereby flux in the magnets produced by the windings will exert a braking action opposing rotation of ,the discs HIT-498 in a well known manner. The windings III and H2 are energized across the terminals of an electric generator I I3 driven by the shaft I as described hereinbefore.

The two spiders 96 and '97 are driven in onposite directions by power from the shaft I. and this may conveniently be done by providing gear teeth on the peripheries of the spiders mesl1- ing them together, as at IM and driving one of the spiders by a gear II5 on the shaft I. For simplicity of description it is assumed that the two spiders and 91 are of equal diameter, as are the two pairs of differential gears associated with the spiders respectively, and as are the pinions Hi l-I95.

'9 With this arrangement,;the discs I01 and; I08

. are driven in opposite directions and the pinions I04 and I05 tend to rotate in opposite directions and exert opposite torques on the governor shaft 56.- If the two discs I01 and I08have equal br ak-,

ing torques applied thereto, the torques; -o f the pinions I04 and I05 will be equal and the governor shaft 56 will remain at rest or come to rest if rotating. If the braking torquesof one;disc is made greater than that of the othenthe torque on The windings III and H2 are subjected toithe potential of the generator 3 as shown. One of the magnets, say the magnet H0, is made of sufficiently small cross-sectional areaand it is energized sufliciently by the winding IIZ sothat it is at all times substantially saturated,.whereby increase or decrease of potential. on its winding produces no change or only a small change in the flux of the magnet.

The magnet I09, however, is energized by its winding I'II below saturation. The cross-sectional area of the magnet I09 is. predetermined so that it produces the same electro-dynamic drag on the discs I01 as does the saturatedmagnet I I0 on the disc I08 when the generator potential is normal.

It follows that magnetism in the. magnet .I I0, remains substantially constant whereas ,magnetism in the magnet I09 rises and falls with changes of potential, and that both magnets ,produce the same braking effect when thexpotential is normal.

If the shaft I should tend to increase in speed and cause the generator voltage torideabove normal, magnetism in the magnet I09 will increase and produce greater drag on the disc I01 than that on the disc I08 produced bythe magnet I I0, and conversely if the shaft I should tend to decrease in speed and lower the potential below normal the magnet I09 will produce less drag thanthemagnetllfl.

It follows thatif the shaft I, should tend'to increase in speed, the rheostat arm I 6 will beturned in one direction, and if it should tend todecrease in speed it will be turned in the other direction, and in either direction will neutralize the change of speed and restore the speed to the preselected value, and the rheostat arm I6 will come to rest in a corresponding position. It is not essential that the magnet IIO be saturated. 'The operation will be substantially as described if it be more nearly saturated than the magnet I09.

In Fig. 7 is illustrated a modification of the arrangement of Fig. 6. In this form instead of driving the two differential spiders 96 and- 91 by-the shaft l, a supplemental-motor. I I6 is provided for this purpose. A'squirred cage induction motor is shown, but any type of motor may be provided,

and it is immaterial whether it is strictly speaking a constant speed motor or not, inasmuch as the absolute speed at which the spiders are driven Qbviously, the generator of Fig. 6 may be an al- -ternator and the current for energizing the brak- .-ing magnets may be alternating current; or it t'ri'fugal type. It. comprises a pair of differential gearing'spiders I I1 and 118 provided respectively with bevel gearteeth H9 and I20 mutually meshed as at I2I; an'dthe'spider II1 has also radical or spur teeth I22 meshedas at I23 with I the teeth on the above described gear M5 on the load shaft I, whereby the spiders H1 and H8 are driven in opposite directions by the load shaft. The spider I'I1 rotatably supports pinions I 24--I 24 meshed with differential gearsv I25 and I26; and the spider II8 rotatably supports pinions I21I'21meshed with differential gearsl28 I and I29.

'The differential'gears I25 and I28 respectively drive bevelgears I30 and I3I; both of which mesh with a single bevel gear I32 connected'to the governor shaft 56, the rotation of which moves the rheostat arm I6 over the resistor I5 for the purposes hereinbefore described.

The differential gear I29 rotatably drives a shaft I33u'pon'which is splined for rotational movement with the'shaft and axial movement v thereon, a relatively. thin disc I34 yieldingly held toward the differential gear I29 by a compression spring I35. The differential gear I26 drives a shaft I36 on which is similarly splined a disc I31, and a compression spring I38 yieldingly holds the disc I31 away from the differential gear I26.

The disc I34 is of larger diameter than the disc I31 and the periphery of the disc I31 engages the face of the disc I34 and the two discs are maintained in positive frictional mutual engagement by the spring I35, whereby one may drive the other. The disc I31 may move or be moved axially along the shaft I36 and its diameter is such that for one axial position, namely that illustrated in solid line, the radius of the circle of contact on the disc I34 is the same as the radius of the disc I31; whereby both discs are constrained to rotate at the same velocity 'or revolutions per minute; and when the disc'l31 is moved inwardly and'similarly if the disc I31 be moved in'the'other say to the dotted line position A, the disc I34 will be constrained torotate faster than the disc I31,

"direction say to the dotted line position B, the

disc I34 will be constrained to rotate slower than the disc I31.

Mounted on the shaft I36 is a head I39 pivoted 1 towhichis a pair of governor ball arms I40 upon which are pivoted centrifugal governor balls 'balls towards the head I39 and upon rotation of the shaftl36the balls tend'to move'outwardly "against the tension of the springs.

The arms I40-I40 areconnectedtothe disc I31 or to a hub From the foregoing description it will be apparent that when the spiders H1 and H8 are driven the otherQ If the :disc I31 is in the position in which both discs rotate 'at thesame speed, the

-1 1 bevel gears I39-I-3I will tend to rotate at the same speed, but sincethey are both geared to the gear I32 they will remain at rest and the governor shaft 55 will remain at rest.

Movement of the governor balls I4I'-I4I outwardly acting through the links I44-I44, will move the disc I31 inwardly, thereby causing one bevel gear I39 or I3I to rotate faster than the other and turn the bevel gear I32, and'the-governor shaft 56 in'one direction. If the balls I4I move inwardly and thereby move the disc 131 outwardly, the governor shaft similarly is caused to rotate inthe other direction,

The tension of the governor spring I42-I42 is predetermined to overcome outward movement of the balls and position the discs at'the one-to-one ratio described, when the load shaft I which is drivingthe balls is rotating'at the predetermined or preselected speed. Thus it follows that at the preselected speed'of the load'shaftl', the governor shaft 56 remains at rest, and upon an increase or decrease of that speed the governor shaft 56 is rotated in one direction or the other to effect restoring of the load shaft speed to the preselected value as hereinbefore described, whereupon the balls I4I again take up 'the'position corresponding to the one-to-one ratio of the discs.

The head I39 may be positioned axially along the shaft I36 to change the tension of the spring I42-I42 by means of a pair of lock nuts 145-445 threaded on the shaft I36; and by means of'the adjustment thus provided the governor shaft '56 may be caused to remain at rest when the load shaft I is rotating at the preselected speed, or, upon changing the position of the head I39, the speed or the load shaft may be'brought to any desired speed and thereby be'pre'determined.

In the governor of Fig. lthespe'ed of the load shaft I may similarly be determined by adjustment of the tension'of'the'springfl'by the screw 43 and in the governor ofFigJGt'he speed of the load shaft may be predetermined by adjusting the screw 99; and by the governor of Fig. '7 the constant speed may be adjustably varied by means of an adjustable resistor inthe circuit of the'winding III.

In Figs. 9 and I'have illustrated a's'tructure by which'the embodiment of Fig. 1 may be practiced. It comprises a tubular laminated stator I45 through which a cylindrical series or cage of conductor bars I41 are projected in suitable perforations therein and riveted over at the ends as at I48--I49. The end plates are clampedbetween end bells I59 and I5I 'by bolts I52 and have feet I53 thereon for mounting upon a base.

The end bell I5I has an end plate I54 mounted thereon. The endplate I54 supports a ball bearing I 55 and the end bell proper I5I supports a ball bearing I56, the two ball bearings I55 and I 56 being axially aligned and axially spaced apart a substantial distance for stability and a shaft I51 is rotatably supported on the ball bearings.

A rotor I58 is mounted on the shaft I51 and this may be conveniently accomplished by providing a central annular hub 159 connected to I the rotor proper I58 by spokes I69 and bolting the hub I59 to a flange IBI on the shaft I51.

The rotor I58 comprises a generally tubular body I62 on which is mounted a tubular laminated structure I63 throug-h'whichare projected conductor bars I54 riveted over at the opposite ends as at I65 upon end plates I6GI66. The spokes I99I99 are preferably formed as the vanes of a fan for cooling purposes to be referred to.

The shaft 151 'has mounted thereon a ball bearing I 61 and this may conveniently be provided for by providing on the shaft I51 a coaxial tubular flange I 58 upon the'outer periphery of which the hub I59 is telescoped to center it and within which the-ball bearing 151 is fitted.

A field element shaft I69 has the inner end thereof supportedin the ball bearing I61, and the outer end'thereof is supported in a-ball bearing I19 mountedi'n the end bell I50. The field element shown generally at I-1I comprises a hub I12 keyed upon the shaft I69, and spokes I13 connecting the hub to an-annular generally tubular body I14; and upon the'body H4 is mounted a plurality of field poles I15 preferably constructed from laminated iron. The laminations of the field poles I15 are clamped together by long rivets I1Ii projected through perforations in thelaminations and riveted over at their ends as fat l11-|11 upon end plates I'M-I18, the radially outer ends of which as at I19--I19 are bent outwardly oppositely in the axialdirection, whereby the end plates I18 provide seats, for supporting and positioning direct current field energizing windings I89--'I'80. The field poles I15 are secured to the body I14 preferably by the structure shown in Fig. 10 in connection with Fig. 9 in which it is shown that the laminations I15 are dove-tailed as at I8I into the body I14 and tightly engaged therewith by wedges I82 and prevented from axial shifting by annular plates I83--I83 secured upon the body 114 in overlapping relation to the laminations I15 by screws I84--I84.

The'windings I89 mayall be'oonnected in series and to two collector rings 1 85 and 186 mounted upon insulators 181-481 on the shaft I59; and brushes 188-188, 'fragmentarily shown engage the collector rings by which current from an external "source maybe conducted thereto, the bracket supports for the 'brushes I88 have been omitted from the "drawing'tosimplify it but such brush supporting brackets being well known in this art.

The shaft I69 extends outwardly from the end bell I59 as at I85 by which it may be connected tothe aforesaid source of power at variable speed.

Rotation of the shaft 169 by the variable speed power source, rotating the field poles I51, produces alternating current in the bars I41 which reacting upon the rotor 158 rotates it and the shaft I51. The shaft I51 extends outwardly through the end bell plate t54-as at I85 whereby it may be connected to the loadto bedriven, and tothe hereinbefore described governor for controlling energization of the fieldwindings I- I80 for'the-purposes described in connection with changes and modifications which come within the'scope 'of'the'appended claims.

I claim:

1. ma power transmission, a stationary laminated stator element having electrical conduc- "tors inductively associated therewith; a directcurrent-energized field element arranged to be 13 rotated within the stator element and to generate alternating current in the conductors and produce a rotary magnetic field in the stator and comprising a circular series of salient field poles having energizing windings connected in series in an energizing circuit; a laminated motor rotor having electric conductors, inductively associated therewith and arranged to rotate within the stator to be rotatably driven by the rotary magnetic field in the stator.

2. In a power transmission, a stationary laminated tubular stator carrying a cage of conductor bars short circuited at end plates thereon; a direct-current-energized field element disposed within the stator and arranged to be rotated therewithin and generate current in the bars and produce a rotar magnetic field in the stator and comprising a, circular series of salient field poles having energizing windings connected in series in an energizing circuit; a motor rotor comprising a laminated body carrying a cage of conductor bars short circuited at end plates thereon disposed within the stator and arranged to be rotatively driven by the rotating magnetic field in the stator and a rotary controller driven responsive to speed of the rotor comprising means to vary the current in the energizing circuit to maintain the rotor speed substantially constant.

3. In a power transmission, a stationary laminated tubular stator carrying a cage of conductor bars short circuited at end plates thereon; a direct-current-energized field element disposed within the stator and arranged to be rotated therewithin at variable speed and generate current in the bars and produce a rotary magnetic 3 field in the stator and comprising a. circular series of salient field poles having energizing windings connected in series in an energizing circuit; a motor rotor comprising a laminated body carrying a cage of conductor bars short circuited at 14 end plates thereon disposed within the stator and arranged to be rotatively driven by the rotating magnetic field in the stator; a controller comprising a movable element movable alter nately to different positions to increase or decrease the energization of the field element to maintain the rotor speed constant for variations of speed of the field element; a transmission to communicate rotary movement of the rotor to the movable element; and means responsive to rotor speed above and below a preselected speed respectively to actuate the transmission to effect communication of rotary movement to the movable element in alternate directions respectively, and to interrupt said communication at said preselected speed.

4. In a power transmission, a tubular stator element comprising short circuited conductors; a direct-current-energized field element rotatable within the stator to generate current in the conductors and produce a rotary magnetic field in the stator and comprising a circular series of salient field po les having energizing windings connected in series in an energizing circuit; and a rotor comprisin short circuited conductors and rotatable within the stator and driven by the rotary magnetic field.

LEV A. TROFIMOV.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 5 Number Name Date 1,158,243 Lakey et al. Oct. 26, 1915 1,504,951 Hall Aug. 12, 1924 1,658,972 Cordes Feb. 14, 1928 1,848,091 Winther Mar. 1, 1932 

